DRUG INTERACTIONS Drug Interactions
Local Anesthetics: Administration of DepoDur three minutes after a 3-mL test-dose (lidocaine 1.5% and epinephrine 1:200,000) increases peak serum concentrations of morphine (See CLINICAL PHARMACOLOGY). Increasing the interval between the test dose and DepoDur administration to at least 15 minutes minimizes this pharmacokinetic interaction.
Safety and efficacy of DepoDur when used in conjunction with therapeutic epidural doses of lidocaine with epinephrine (for conduction anesthesia) have not been studied in clinical trials.
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OVERDOSAGE
Overdosage of morphine is characterized by respiratory depression, with or without concomitant CNS depression. In severe overdosage, apnea, circulatory collapse, cardiac arrest and death may occur. The conditions that might cause an overdosage situation may vary from patient to patient. A DepoDur dose that is within the labeled dosing guidelines may be found to be more than could be tolerated by an individual patient. During post-marketing experience, spontaneous cases of apnea, respiratory arrest, and cardiac arrest have been reported after administration of labeled DepoDur doses (see WARNINGS and ADVERSE EVENTS). Since respiratory arrest may result either through direct depression of the respiratory center or as the result of hypoxia, attention should primarily be given to the establishment of adequate respiratory exchange through provision of a patent airway and institution of assisted or controlled ventilation. Opiates administered in addition to DepoDur to manage pain may precipitate or worsen adverse events such as respiratory depression. Additional opiates should be administered with caution.
The opiate antagonist, naloxone, is a specific antidote. An initial dose of 0.4 to 2 mg of naloxone should be administered intravenously, simultaneously with respiratory resuscitation. If the desired degree of counteraction and improvement in respiratory function is not obtained, naloxone may be repeated at 2- to 3-minute intervals. If no response is observed after 10 mg of naloxone has been administered, the diagnosis of opiate-induced, or partial opiate-induced, toxicity should be questioned. Intramuscular or subcutaneous administration may be used if the intravenous route is not available.
As the duration of effect of naloxone is considerably shorter than that of DepoDur, repeated administration or continuous infusion of naloxone may be necessary. Patients should be closely observed for evidence of recurrence of respiratory depression.
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CONTRAINDICATIONS
DepoDur is contraindicated in patients with known hypersensitivity to morphine, morphine salts, or any components of the product. DepoDur, as with all opiates, is contraindicated in patients with respiratory depression, acute or severe bronchial asthma, and upper airway obstruction. Any contraindications for an epidural injection preclude the administration of DepoDur. DepoDur, as with all opiates, is contraindicated in any patient who has or is suspected of having paralytic ileus. DepoDur should not be used in patients with suspected or known head injury or increased intracranial pressure.
DepoDur is an opiate analgesic which causes vasodilatation that may exacerbate hypotension and hypoperfusion and, therefore, is contraindicated in circulatory shock.
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